The basic structure and operation of a cellular radiotelephone system are well known and have been disclosed in a number of publications. See, for example the January 1979 issue of The Bell Systems Technical Journal; and Specification EIA IS-3B entitled "Cellular System Mobile Station--Land Station Compatibility Specification" (July, 1984, Electronic Industries Association).
Signal-strength analyzers are employed in the prior art to measure and report signal strength information of the radio frequency communication channels which are used in cellular radiotelephone systems. This information is used to ensure reliable operation over the service provider's coverage area. In mature cellular radiotelephone systems, where the cell sites have grown to be very dense, the measurement of signal strength alone is not enough to ensure the reliable operation of the cellular system.
Providers of cellular radiotelephone service need to ascertain whether or not high quality cellular service is being provided to all areas where the cellular radiotelephone system provides service. Current means for determining the quality of service provided by a cellular radiotelephone system are manually intensive requiring a person at the mobile and fixed stations of a cellular radiotelephone conversation. These people place and receive cellular radiotelephone calls, monitor the progress of the call, rate the clarity of the audio for the call, note the graphical location of the mobile station call, and record success or failure for each call placed or received.
This technique of measuring cellular radiotelephone system quality is very tedious, and is highly susceptible to human error especially after long periods of data collection. The manual rating of the audio quality during each cellular radiotelephone call is especially vulnerable to human interpretation. One person may rate the audio quality of a call acceptable while another person would rate the audio quality of the same call unacceptable. Of even greater concern, the same person may rate equal audio quality acceptable one day and unacceptable the next day.
Additionally, when competitive comparisons between multiple cellular radiotelephone service providers are required or when differing cellular radiotelephone technologies need to be compared, multiple sets of people need to be employed to complete each comparison.
Therefore, cellular radiotelephone service providers need to rely upon automated, in-field, geographically-located recordings of call progress and measurements of the cellular radiotelephone audio quality to either verify high quality cellular coverage or identify problem areas which need attention. The measurement of cellular radio telephone system quality needs to be repeatable between days, weeks, months and even years of testing for statistical accuracy.